1. Field of the Invention
This present invention relates to heterocyclic compounds and analogues thereof and their use as inhibitors of Mitogen-Activated Protein Kinase-Activated Protein kinase-2 (MAPKAP-k2). The present invention also related to a method for preventing or treating a disease or disorder that can be treated or prevented by modulating the activity of MAPKAP-K2 in a subject, and to pharmaceutical compositions and kits that include these MAPKAP-K2 inhibitors.
2. Description of Related Art
Mitogen Activated Protein Kinases (MAPKs) are members of signal transduction pathways that change cell physiology in response to external stimuli by activating a variety of downstream signaling genes products. These gene products control diverse cellular functions such as the production of pro-inflammatory cytokines involved in establishing and maintaining specific human diseases. The MAPKs are activated by phosphorylation on specific residues within the activation loop sequence by specific upstream MAPK kinases (MKKs) in response to a cellular activation signal. In turn, the MAPKs activate a variety of downstream gene products. There are four major classes of MAPKs: 1) the archetypal Extracellular Regulated kinases (ERKs), 2) the c-jun N-terminal kinases (JNKs), 3) the p38 MAPKs and finally, 4) the ERK5 or BigMAPKs. The MAPK pathways are involved in alterations in cell physiology resulting from cell stimulation. They control various cell processes such as: cell death, cell cycle machinery, gene transcription and protein translation.
Of particular relevance to this invention is the p38 MAPK family (also known as p38, SAPK2a, RK, MPK2, Mxi2 and CSBP). These kinases, most notably the p38alpha and p38beta isoforms, can activate a wide variety of regulatory proteins. In this manner, p38 can diversify downstream signaling leading to a wide variety of cellular outcomes. Central to the signal transduction process initiated by p38 activation is MAPKAP-K2. Most of the physiological outcomes of MAPKAP-K2 have been established using mice genetically deficient in MAPKAP-K2 (designated MAPKAP-K2(−/−)). A significant phenotype of the MAPKAP-K2(−/−) mice is that pro-inflammatory cytokine production is inhibited following stimulation of splenocytes with lipopolysaccharide (LPS). Specifically, the production of tumor necrosis factor-alpha (TNF-alpha) is blocked by 92%, interleukin-1beta (IL-1-beta) is blocked by 40%, IL-6 is blocked by 87% and interferon-gamma (IFN-gamma) is blocked by 86%. This phenotype cannot be rescued by the expression of a kinase dead MAPKAP-K2 mutant, indicating that the kinase function of MAPKAP-K2 is required for proinflammatory cytokine production. Thus, an inhibitor of MAPKAP-K2 kinase activity has the potential to exhibit the same inhibitory effects on the production of proinflammatory cytokines.
MK2 activates a number of substrates, including the mRNA binding protein, tristetraproline (TTP). TTP expression is induced by proinflammatory stimuli such as lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-alpha). TTP binds to the AU-rich element within the 3′-untranslated region of the TNF-alpha transcript resulting in a decrease in TNF-alpha mRNA stability. TTP(−/−) mice exhibit many defects including arthritis and systemic lupus erythematosis-like symptoms presumably resulting from an increase in circulating TNF-alpha levels. Data from in vivo studies with MK2(−/−) indicate that the repressive effects of TTP on both TNF-alpha and interleukin-6 (IL-6) production are downstream of MK2 further establishing p38-MK2-TTP as a critical signaling sequence for the production of proinflammatory cytokines.
Elevated levels of proinflammatory cytokines are associated with a number of diseases such as toxic shock syndrome, rheumatoid arthritis, osteoarthritis, diabetes and inflammatory bowel disease. In these diseases, chronic elevation of inflammation exacerbates or causes much of the pathophysiology observed. For example, rheumatoid synovial tissue becomes invaded with inflammatory cells that result in destruction to cartilage and bone. Studies suggest that inflammatory changes mediated by cytokines may be involved in endothelial cell pathogenesis including restenosis after percutaneous transluminal coronary angioplasty (PTCA). An important and accepted therapeutic approach for potential drug intervention in these diseases is the reduction of pro-inflammatory cytokines such as TNF-alpha and IL-1-beta. Several biological agents directed against these pro-inflammatory cytokines (anti-TNF antibodies, a soluble TNF receptor and an IL-1 receptor antagonist) have been FDA approved for the treatment of RA, Crohn's disease and psoriatic arthritis; Abbott Laboratories markets HUMIRA® (Adalimumab) for the treatment of rheumatoid arthritis (RA).
A soluble TNF-alpha receptor has been engineered that interacts with TNF-alpha. The approach is similar to that described above for the monoclonal antibodies directed against TNF-alpha; both agents bind to soluble TNF-alpha, thus reducing its concentration. One version of this construct, Enbrel® (Immunex, Seattle, Wash.), is marketed for the treatment of rheumatoid arthritis, psoriasis, ankylosing spondylitis, and psoriatic arthritis. Another version of the TNF-alpha receptor, Ro 45-2081 (Hoffman-LaRoche Inc., Nutley, N.J.) has demonstrated efficacy in various animal models of allergic lung inflammation and acute lung injury. Ro 45-2081 is a recombinant chimeric molecule constructed from the soluble 55 kDa human TNF receptor fused to the hinge region of the heavy chain IgG1 gene and expressed in eukaryotic cells.
Proinflammatory cytokines such as TNF-alpha and IL-6 are also important mediators of septic shock and associated cardiopulmonary dysfunction, acute respiratory distress syndrome (ARDS) and multiple organ failure. In a study of patients presenting with sepsis, a correlation was found between TNF-alpha and IL-6 levels and septic complications. TNFα has also been implicated in cachexia and muscle degradation, associated with HIV infection. Obesity is associated with an increase incidence of infection, diabetes and cardiovascular disease. Abnormalities in TNF-alpha expression have been noted for each of the above conditions. It has been proposed that elevated levels of TNF-alpha are involved in other eating related disorders such as anorexia and bulimia nervosa. Pathophysiological parallels are drawn between anorexia nervosa and cancer cachexia. An inhibitor of TNF-alpha production, HU-211, was shown to improve the outcome of closed brain injury in an experimental model. Atherosclerosis is known to have an inflammatory component and cytokines such as IL-1 and TNF have been suggested to promote the disease. In an animal model an IL-1 receptor antagonist was shown to inhibit fatty streak formation.
TNF-alpha levels are elevated in airways of patients with chronic obstructive pulmonary disease and it may contribute to the pathogenesis of this disease. Circulating TNFα may also contribute to weight loss associated with this disease. Elevated TNF-alpha levels have also been found to be associated with congestive heart failure and the level has been correlated with severity of the disease. In addition, TNF-alpha has been implicated in reperfusion injury in lung, kidney, and the nervous system. TNF-alpha is also a potent osteoclastogenic agent and is involved in bone resorption and diseases involving bone resorption. It has also been found highly expressed in chondrocytes of patients with traumatic arthritis. TNF-alpha has also been shown to play a key role in the development of glomerulonephritis.
The proinflammatory cytokine IL-6 has been implicated with the acute phase response. IL-6 is a growth factor in a number in oncological diseases including multiple myeloma and related plasma cell dyscrasias. It has also been shown to be an important mediator of inflammation within the central nervous system. Elevated levels of IL-6 are found in several neurological disorders including AIDS dementia complex, Alzheimer's disease, multiple sclerosis, systemic lupus erythematosus, CNS trauma and viral and bacterial meningitis. IL-6 also plays a significant role in osteoporosis. In murine models it has been shown to effect bone resorption and to induce osteoclast activity. Marked cytokine differences, such as IL-6 levels, exist in vivo between osteoclasts of normal bone and bone from patients with Paget's disease. A number of cytokines have been shown to be involved in cancer cachexia. The severity of key parameters of cachexia can be reduced by treatment with anti IL-6 antibodies or with IL-6 receptor antagonists. Several infectious diseases, such as influenza, indicate IL-6 and IFN alpha as key factors in both symptom formation and in host defense. Overexpression of IL-6 has been implicated in the pathology of a number of diseases including multiple myeloma, rheumatoid arthritis, Castleman's disease, psoriasis, post-menopausal osteoporosis and juvenile idiopathic arthritis. Compounds that interfered with the production of cytokines including IL-6, and TNF were effective in blocking a passive cutaneous anaphylaxis in mice. More recently, a humanized antibody directed against the IL-6 receptor, demonstrated efficacy in a randomized double-blind pilot human clinical study by significantly reducing the Crohn's disease activity index.
IFN-gamma has been implicated in a number of diseases. It has been associated with increased collagen deposition that is a central histopathological feature of graft-versus-host disease. Following kidney transplantation, a patient was diagnosed with acute myelogenous leukemia. Retrospective analysis of peripheral blood cytokines revealed elevated levels of GM-CSF and IFN-gamma. These elevated levels coincided with a rise in peripheral blood white cell count. The development of insulin-dependent diabetes (Type 1) can be correlated with the accumulation in pancreatic islet cells of T-cells producing IFN-gamma. IFN-gamma along with TNF, IL-2 and IL-6 lead to the activation of most peripheral T-cells prior to the development of lesions in the central nervous system for diseases such as multiple sclerosis (MS) and AIDS dementia complex. Atherosclerotic lesions result in arterial disease that can lead to cardiac and cerebral infarction. Many activated immune cells are present in these lesions, mainly T-cells and macrophages. These cells produce large amounts of proinflammatory cytokines such as TNF, IL-1 and IFN-gamma. These cytokines are thought to be involved in promoting apoptosis or programmed cell death of the surrounding vascular smooth muscle cells resulting in the atherosclerotic lesions. Allergic subjects produce mRNA specific for IFN-gamma following challenge with Vespula venom. The expression of a number of cytokines, including IFN-gamma has been shown to increase following a delayed type hypersensitivity reaction thus indicating a role for IFN-gamma in atopic dermatitis. Histopathologic and immunohistologic studies were performed in cases of fatal cerebral malaria. Evidence for elevated IFN-gamma amongst other cytokines was observed indicating a role in this disease. The importance of free radical species in the pathogenesis of various infectious diseases has been established. The nitric oxide synthesis pathway is activated in response to infection with certain viruses via the induction of proinflammatory cytokines such as IFN-gamma. Patients, chronically infected with hepatitis B virus (HBV) can develop cirrhosis and hepatocellular carcinoma. Viral gene expression and replication in HBV transgenic mice can be suppressed by a post-transcriptional mechanism mediated by IFN-gamma, TNF and IL-2. IFN-gamma can selectively inhibit cytokine induced bone resorption. It appears to do this via the intermediacy of nitric oxide (NO) which is an important regulatory molecule in bone remodeling. NO may be involved as a mediator of bone disease for such diseases as: rheumatoid arthritis, tumor associated osteolysis and postmenopausal osteoporosis. Studies with gene deficient mice have demonstrated that the IL-12 dependent production of IFN-gamma is critical in the control of early parasitic growth. Although this process is independent of nitric oxide the control of chronic infection does appear to be NO dependent. NO is an important vasodilator and convincing evidence exists for its role in cardiovascular shock. IFN-gamma is required for progression of chronic intestinal inflammation in such diseases as Crohn's disease and inflammatory bowel disease (IBD) presumably through the intermediacy of CD4+ lymphocytes probably of the TH1 phenotype. An elevated level of serum IgE is associated with various atopic diseases such as bronchial asthma and atopic dermatitis. The level of IFN-gamma was negatively correlated with serum IgE suggesting a role for IFNgamma in atopic patients.
The proinflammatory cytokine, IL-1-beta, is partially controlled by MAPKAP-k2. Hence, inhibition of MAPKAP-k2 may impact IL-1-beta dependent processes. IL-1 has been implicated as an immunological effector molecule in a large number of disease processes. IL-1 receptor antagonist (IL-1ra) had been examined in human clinical trials. Efficacy has been demonstrated for the treatment of rheumatoid arthritis. In a phase III human clinical trial IL-1ra reduced the mortality rate in patients with septic shock syndrome. Several other diseases affected by IL-1 include Adult Onset Still's disease, macrophage auto-activation syndromes, Muckle-Wells syndrome, Familial Cold Autoinflammatory Syndrome and Neonatal Onset Multisystem Inflammatory Disease. Patients with Muckle-Wells syndrome exhibiting systemic inflammation were treated with anakinra (IL-1ra), leukocytosis serum amyloid A, C-reactive protein and local inflammatory arthritis were reduced with a few days demonstrating that systemic inflammation is IL-1 mediated. Osteoarthritis is a slow progressive disease characterized by destruction of the articular cartilage. IL-1 is detected in synovial fluid and in the cartilage matrix of osteoarthritic joints. Antagonists of IL-1 have been shown to diminish the degradation of cartilage matrix components in a variety of experimental models of arthritis. Nitric oxide (NO) is a mediator of cardiovascular homeostasis, neurotransmission and immune function; recently it has been shown to have important effects in the modulation of bone remodeling. Cytokines such as IL-1 and TNF are potent stimulators of NO production. NO is an important regulatory molecule in bone with effects on cells of the osteoblast and osteoclast lineage. The promotion of beta-cell destruction leading to insulin dependent diabetes mellitus shows dependence on IL-1. Some of this damage may be mediated through other effectors such as prostaglandins and thromboxanes. IL-1 can effect this process by controlling the level of both cyclooxygenase II and inducible nitric oxide synthetase expression.
Inhibitors of cytokine production are expected to block inducible cyclooxygenase (COX-2) expression. COX-2 expression has been shown to be increased by cytokines and it is believed to be the isoform of cyclooxygenase responsible for inflammation. Accordingly, inhibitors of MAPKAP-k2 reducing the production of cytokines such as IL-1, would be expected to exhibit efficacy against those disorders currently treated with COX inhibitors such as the familiar NSAIDs. These disorders include acute and chronic pain as well as symptoms of inflammation and cardiovascular disease.
Elevation of several cytokines has been demonstrated during active inflammatory bowel disease (IBD). A mucosal imbalance of intestinal IL-1 and IL-1ra is present in patients with IBD. Insufficient production of endogenous IL-1ra may contribute to the pathogenesis of IBD. Alzheimer disease is characterized by the presence of beta-amyloid protein deposits, neurofibrillary tangles and cholinergic dysfunction throughout the hippocampal region. The structural and metabolic damage found in Alzheimer disease is possibly due to a sustained elevation of IL-1. A role for IL-1 in the pathogenesis of human immunodeficiency virus (HIV) has been identified. IL-1ra showed a clear relationship to acute inflammatory events as well as to the different disease stages in the pathophysiology of HIV infection. IL-1 and TNF are both involved in periodontal disease. The destructive process associated with periodontal disease may be due to a disregulation of both IL-1 and TNF.
IL-1 has also been shown to induce uveitis in rats which could be inhibited with IL-1 blockers. Cytokines including IL-1, TNF and GM-CSF have been shown to stimulate proliferation of acute myelogenous leukemia blasts. IL-1 was shown to be essential for the development of both irritant and allergic contact dermatitis. Epicutaneous sensitization can be prevented by the administration of an anti-IL-1 monoclonal antibody before epicutaneous application of an allergen. Data obtained from IL-1 knock out mice indicates the critical involvement in fever for this cytokine A variety of cytokines including TNF, IL-1, IL-6 and IL-8 initiate the acute-phase reaction which is stereotyped in fever, malaise, myalgia, headaches, cellular hypermetabolism and multiple endocrine and enzyme responses. The production of these inflammatory cytokines rapidly follows trauma or pathogenic organism invasion.
This application discloses compounds that have the ability to inhibit TNF-alpha. Compounds disclosed herein are indicated to be effective in treating the following diseases: Rheumatoid arthritis, psoriasis, crohn's disease, dementia associated with HIV infection, glaucoma, optic-neuropathy, optic neuritis, retinal ischemia, laser induced optic damage, surgery or trauma-induced proliferative vitreoretinopathy, cerebral ischemia, hypoxia-ischemia, hypoglycemia, domoic acid poisoning, anoxia, carbon monoxide or manganese or cyanide poisoning, Huntington's disease, Alzheimer's disease, Parkinson's disease, meningitis, multiple sclerosis and other demyelinating diseases, amyotrophic lateral sclerosis, head and spinal cord trauma, seizures, convulsions, olivopontocerebellar atrophy, neuropathic pain syndromes, diabetic neuropathy, HIV-related neuropathy, MERRF and MELAS syndromes, Leber's disease, Wernicke's encephalophathy, Rett syndrome, homocysteinuria, hyperprolinemia, hyperhomocysteinemia, nonketotic hyperglycinemia, hydroxybutyric aminoaciduria, sulfite oxidase deficiency, combined systems disease, lead encephalopathy, Tourett's syndrome, hepatic encephalopathy, drug addiction, drug tolerance, drug dependency, depression, anxiety and schizophrenia. In addition, compounds disclosed herein are useful for treating acute and chronic inflammation in the lung caused by inhalation of smoke such as cigarette smoke. TNF-alpha anatagonists are apparently also useful for the treatment of endometriosis, see EP 1022027 A1, as well as rheumatoid arthritis, psoriasis, ankylosing spondylitis, and psoriatic arthritis. The p38MAP kinase pathway plays an role in B. burgdorferi-elicited inflammation and may be useful in treating inflammation induced by the Lyme disease agent.
As noted above, inhibition of cytokine production will be beneficial in the treatment of cytokine mediated diseases. Therefore a need exists for small molecule inhibitors for treating these diseases with optimized efficacy, pharmacokinetic and safety profiles.